Refrigeration



Nov. 3o, 1943. C. c. @ONS 2,335,389

REFHIGERATION Filed Jan. 51, 193s 'INVENTOR ATTORNEY BYMAgE-M 'tion of the gas 4 4 of Figure 2 and looking' l Y Patented Nev. l30, A1943 curas c. owns, Nomi canton,

Ohio, assignor to The Hoover Company, North Canton, Ohio, a

corporation of Ohio `rimaniamo January s1, 193s. serial No. masso 12 Claims. This invention relates to refrigerating apparar tus and more particularly to a means and method of regulating the flow of an -inert gas through certain parts of a refrigerating system.

In three fluid absorption refrigerating systems as heretofore constructed, the inert gas has been circulated by gravity or by some power-driven means. such as an electric motor-driven fan. These systems sometimes possessed the disadvantage that the rate of flow of the inert gas was not properly proportioned relative to the rate at which liquid refrigerant was supplied to the evaporator to produce refrigeration. As a result of this action, therelwould be insumcient inert gas circulating through the evaporator to produce refrigeration emciently when the Agener-- ator of the system was operating at maximum` Y capacity.` On the other hand. too much gas would be supplied to the evaporator to produce refrigeration emclently when the generator was operating at low capacity.

, Accordingly. 'it is an object of this invention to .overcome the 'difilculties above enumerated by properly proportioning the rate of flow of the inert gas and the rateat which refrigerant is generated in the boiler. More specifically, I propose positively to circulate the inert gas by a mechanism having a constant gas circulating capacity and to regulate the actual rate of circulaby throttling the same in accordance with the rate at which heat is supplied to the refrigerant generator. l

Other and further objects of the invention will become apparent as the vdescription proceeds when takenin connection with the accompanying drawing, in which:

Fig. 1 is a diagrammatic representation of`a refrigerating system embodying my invention;

- Fig. 2 is a sectional mechanism drawn to an enlarged scale;

Fig. 3 is a view taken along the line 3-3 of Figure 2 and lookingin the direction of the arrows; and V Fig. 4 is a sectional view taken along the. line in the direction of refrigerating'system comprising a boiler B, a

condenser C. anevaporatoli. an absorber A.

(c1. ca -s) conduits to form a plurality of veyed from the gas separation gas and liquid circuits to constitute a complete refrigerating system.

The refrigerating system is suitablycharged with a refrigerant such as ammonia, an absorbent such as water, and an inert pressure equalizing medium such as hydrogen or nitrogen.

Application of heat to the boiler. B liberates refrigerant vapor from the r frigerant absorbent solution therein contained. e refrigerant vapor finds its way into a vapor lift pipe Il and -travels upwardly therethrough in the form of slugs spaced apart by slugs of weak absorption solution in the well known manner. The vapor and solution elevated through the conduit il discharge into a gas separation chamber I2 in which they separate and travel separately lthrough their respective circuits. The

chamber l2 It, the liquid heat exchanger through a conduit the 'upper end of the il, and a conduit IU into tubular inclined air-cooled absorber A. 'I'he weak solution flows downwardly through the detail view of a control The liquid flows -orator in counterriow stream of pressure edualising medium. The reand a circulating fan F driven by an electrical motor M. The refrigerating eiementsiust deintereonnectedby conduit 2| mts the upper por equalizing medium to air-cooled absorber A in counterfiow relationship to a mix"- ture lof inert gas and refrigerant vapor flowing upwardly therethrougln The refrigerant vapor content of the mixture is absorbed by the absorptioxrsolution therebystrengthening its concentration. -The strong. solution is drained from the lower end of the absorber through a conduit Il, liquid heat exchanger Il, and a conduit I1 into the boiler B thus completing the solution circuit.

The refrigerant discharged into the separation chamber i2 is discharged the efrom through a on of a tubular air-cooled condenser C. A.. The conduit 2i includes an air-cooled rectifier It which condenses any vapor of absorption separation chamber I2. The refrigerant vapor is liqueiled in the condenser by heat exchange with ambient air and is dischliaedtherefrom into the evaporator E through a conduit 21.

downwardly through the evaprelationship to a propelled frigerant liquid evapcrates into the pressure produce refrigeration. The lean pressure equalising medium formed in the absorberA is conveyed from the upper` l portion thereofinto the suction inlet oi the circulating fan F gasis placed under pressure bythe circulating fan F and is conveyed Il. The inert gas leaves the outer pass of the weak solution is conp g solution which may pass the by a conduites. The lean inert` therefrom to the outer member of a gas heat exchanger by a conduit gas heat exchanger and enters the bottom' portion of the evaporator E through which Ait travels upwardly in counteriiow relationship to the liquid refrigerant as the refrigerant evaporates-therefinto. The rich inert gas formed in the evap- 'oratoris returned from the upper end thereof into the inner pass of the gas heat exchanger 21, from which vit is conveyed through a conduit 29 including a throttling device 30 to the bottom portion of the absorber A through which the gas flows upwardly in counterflow relationship to absorption solution as described previously.

A control mechanism which is responsive to evaporator temperature conditions is indicated generally at 23. This control mechanism controls the energization of the motorthrough the electrical conductors 25 and regulates the supply of fuel to a boiler heating gas burner I8 through a fuel supply conduit I9. Preferably the control mechanism modulates the gas fiame in response to variations in'refrigeration demand and energizes the circulating motor except under conditions of substantial shut-*off of the refrigeration;

that is, under conditions suchthat a mere igniting or pilot ame is carried on the gas burner I8.

'I'he control mechanism per se forms no part of this. invention. A preferred form `of control mechanism is 'disclosed in the copending application of Curtis C. Coons and William H. Kitto, Serial No. 160,274, filed August 21, 1937, now Patent No. 2,262,656, dated November 1l, 1941.

` It will be understood that thev refrigerating system disclosed herein is illustrated and described diagrammatically by way of example only. The specific structure of the various elements of the system and the arrangement of the ygas circuit in accordance with the temperature oi such gases. The circulating induction type in which a squirrel cage rotor is motor'M is preferably of the housed within a sealing shell and the field windings are placed without the shell. Such a motor operates at substantially constant speed wherefox' the rate of inert gas circulation would be conparts thereof are susceptibleof wide Variation without departing from the invention.

'I'he vthrottling device.30 includes a cylindrical conduit section 32 which is adalited to be inserted between separated sections of the conduit 29 to form a complete conduit with such separated sections. The conduit 32 is surrounded by a securing sleeve 33 which is suitably secured as by welding to the separated sections of the conduit 29. A cylindrical thermostat housingl 35 projects laterally from the sleeve 33 and extends into the products of combustion discharge flue 20. 'I'he end ofthe sleeve l35 positioned within the conduit 20 is sealed Iby a suitableend plug 36 which-ls securedv to the sleeve 35 as by welding.

A helical bimetallic thermostat 38 is carried within the sleeve 35 and is provided with a laterally projecting end. portion 39 which is anchored I in any suitable manner in the end plug 36. The opposite end of the bimetallic thermostat 38 is provided with a laterally projectingsegment 40 which projects into a slot formed in the end of an enlargement 42 of a shaft 43. 'I'he shaft 43 is suitably journalled in the walls of the conduit section 32. A butterfly valve plate 44 is rigidly secured to the shaft 43 and is adapted completely flow of .the inert gas ilow'ingthroush the inert stant at all times were it not for the throttling The control mechanism will regu-V device 30. late the fiame on the burner and'thereby the rate at which refrigerant is generated in accordance with demand for refrigeration.

on the burner in response to demands for refrigeration. This correspondinglyincreases or decreases the rate at which refrigerant vapor is generated and at which refrigerant liquid is supplied to lthe evaporator E. In order-that the rate of circulation of the inert gas may properly be proportioned with respect to the rate at which refrigerant liquid is supplied to the evaporator, the throttling mechanism 30 is provided.

This mechanism is responsive to flue gas temperatures which are in turn a function of the rate at ,which heat is supplied to the boiler and at which refrigerant vapor is generated. The net result of this mechanism is that the thermostat. operates to open the butterfly valve plate v24 4to full open position when the control mechanism has turned the gas fiame up to its maximum value. The gas conduit 29 will .not beentirely blocked except during periods of complete inactivity of the refrigerating system. 'I'he pilot flame normally provided to ignite the main burner will supply( suicient products of combustion to keep the valve plate 44 slightly open.

From the-description above it will be apparent that I have devised a. refrigerating system in which the inert gas is positively circulated and in which the rate of flow of the inert gas is maintained *in proper relationship to the rate at which. liquid refrigerant is supplied to the evaporator. Obviously, the thermostatic mecha nism 39 could be made responsive to conditions other than the flue gas temperature, for example, the temperature of the condenser or absorber.

,The presentinvention provides a mechanism whereby the refrigerant concentration in the yinert gas and absorption solution is maintained at its optimum value under all conditions of operation. If the concentration of the refrigerant in the rich inert gas is allowed to drop as is the case when only a small quantity of refrigerant.

is supplied to the evaporator and the rate of inert gas circulation is constant,'the absorbing process will proceedinefliciently. On the other hand, if the 'refrigerant concentration in the inert gas is allowed to get too high the evaporating process proceeds in an unsatisfactory manner. i

In the present invention the rate of absorption...

The contro'lmechanism increases or decreases the flame solution circulation is properly proportioned to' the refrigeration demand and rate ofrefrigerant generation by the vapor lift circulating-pump.

The rate of inert gas ,circulation is seared to the refrigerating de mad and rate of refrigerant generation under allxvariations of the load by the throttling valve in the inert gasy circuit.

A Thus, the refrigerantconcentration in any selected portion of the inert .gas circuit-is-.maintained at an optimum value at all refrigerating loads. Consequently, jthe apparatus may be designed for `operation at a selected level of refrigerant concentration at various points and the mechanism of the present invention ,will substantially maintain these concentrations at widely varying rates of refrigeration production.

Since the rate at which the absorption solution is circulated between the boiler and the absorber is a function of the rate at which heat is supplied to the boiler, it follows that the rates of heat supply, inert gas` circulation, absorption solution circulation, and production of refrigeration are all proportioned one to another and are regulated by the demand for refrigeration.

While I have illustrated and described a single embodiment of my inventionf it is to be understood that the invention is not limited thereto but may be embodied in numerous other constructionalA forms and variations without departing from the spirit of the invention or the scopeof the appended claims.

I claim: l. That improvement in the art of refrigeration which includes the steps of Y expelling refrigerant vapor from solution by application of heat thereto, liquefying the vapor so expelled, evaporating the liquefied refrigerant into a propelled' stream of an inert gas, applying a substantially onstant propelling force to the inert gas and `gulating the rate ofA lilow .of the inert gas in :cordance with the rate at which' heat is supplied to generate refrigerant vapor.

2. That improvement in the art of refrigeration which includes the steps of subjecting a solution of yrefrigerant in an absorbent to the action of a iiame, liquefying refrigerant vapor liberated by the action of the flame, evaporating 'the refrigerant liquid so generated into a Y propelled stream of inert gas, and throttling the iiow of the inert gas` directly with variations in the temperature of the products of combustion of the flame.

3. Refrigerating apparatus ycomprising a boiler, a condenser, an evaporator, an absorber, means forming an inert gas circuit including said evapocircuit including said boiler and said absorber, electrical power-driven meansfor circulating an inert gas through said inert gas circuit, and means operative automatically properly to proportion the rate of flow of inert gas to said evaporator land the rate at which liquid refrigerant is supplied thereto under varying refrigerating loads.

4. Absorption refrigerating apparatus including a boiler, a gas burner for heating said boiler, a flue for conveying waste products of combustion from said boiler, means forming a solution circuit including an absorber and said boiler, means forming a pressure equalizing medium circuit including said absorber and an evaporator, power-driven means 'for circulating an inert gas through said -pressure equalizing medium circuit,

a valve in said pressure equalizing medium circuit, and thermostatic means responsive to the temperature of the waste gases in said flue operative to regulate thesetting of said valve.

5. Absorption refrigerating apparatus comprising a pressure equalizing medium circuit including an evaporator and an absorber, powerdriven means for circulating a pressure equalizing medium through said circuit, a boiler for generating refrigerant vapor, means for supplying refrigerant vapor so generated to said evaporator in liquid form, control means responsive to the demand for refrigeration adapted to control the energization of said power driven'means and the rate at which heat is supplied to said assess -boiler, and means for regulating the resistance of said inert gas circuit in accordance with the rate at which heat is supplied to said boiler.

6. Absorption refrigerating apparatus comprising a pressure equalizing medium circuit in- I cluding an evaporator and an absorber, a boiler,

means for supplying refrigerant generatedin said boiler to said evaporator in liquid phase, power driven means for applying a substantially constant circulating force to the pressure equalizing medium to propel the same through said pressure equalizing medium circuit, and means for regulating the flow of said pressure equalizing medium through said-circuit.

7. Absorption refrigerating apparatus comprising a pressure equalizing medium circuit including an evaporator and an absorbena boiler, means for supplyingv refrigerant generated in said boiler -to said evaporator in liquidphase, power drivenv means for circulating pressure equalizing medium through said pressure equalizing medium circuit, and means forI regulating the flow of said pressure equalizing medium through said circuit, said regulating means including a throttling device and a thermostatic regulator therefor.

8. Absorption refrigerating apparatus comprising a pressure .equalizing medium circuit including an evaporator and an absorber, a boiler, means for supplying refrigerant generated in said boiler to said'evaporator in liquid phase, power driven means for applying a substantially constant circulating lforce to the pressure equalizing medium to propel the same through said pressure equalizing medium circuit, and a burner for heating said boiler, and means responsive to the temperature of waste products from said burner for regulating the flow of said pressure equalizing 'medillnL prising a pressure equalizing medium circuit inrator and said absorber, means forming a solution cluding an evaporator and an absorber, a boiler,

means for supplying refrigerant generated in said boiler to said evaporator in liquid phase, power driven means for circulating pressure equalizing medium through saidv pressure equalizing medium circuit, and a burner for heating said boiler, and means responsive to the temperature of 'waste products from said burner for regulating the flow of said pressure equalizing medium, said regulating means including a throttling device, a products of combustion flue for said burner, and a thermostat mounted in heat exchange relation with products flowing through said flue, said thermostat being operatively connected to said throttlirig device.

10. Absorption refrigeratihg apparatus comprising a pressure equalizing medium 'circuit including an evaporator and an absorber, a' boiler, means for 'supplying refrigerant generated in said boiler to said evaporator in liquid phase, and means for regulating the flow of said pressure equalizing medium through said circuit, said reg- A'ulating means including-a throttling device, a

products of combustion flue for said burner, and a thermostat mounted in heat exchange relation with products flowing through said flue, said thermostat being operatively connected to said throttling device. Y'

11. Absorption refrigerating apparatus comprisingan inert gas circuit including an absorber and an evaporator, a solution circuit includins a boiler and said absorber, a constant speed circulator for propelling gases through said inert gas circuit, means for heating said boiler, and

means'for regulating the rate of ow of said gases in accord with the rate of heat supply to said boiler.

12. Absorption' refrigerating apparatus oomprising an inert gas circuit including an absorber I 5 land an evaporator, a solution circuit including a boiler and said absorber, a constant speed'circulator for propelling gases through said inert :as circuit, means tor heating said boiler. means for regulating the rate or now ot said gases in accord with the rate of heat'slmpl! to said boiler and control means responsive to the demand for refrigeration for regulating the rate of heat supply to said boiler and for controlling the opera- 

